Upf service-based packet delay status event exposure service method and device

ABSTRACT

The present disclosure relates to: a communication technique merging IoT technology with a 5th generation (5G) or pre-5G communication system for supporting a data transmission rate higher than that of a 4th generation (4G) communication system such as long term evolution (LTE); and a system therefor. The present disclosure can be applied to intelligent services (for example, smart homes, smart buildings, smart cities, smart cars or connected cars, healthcare, digital education, retail, security- and safety-related services, and the like) on the basis of 5G communication technology and IoT-related technology. According to various embodiments of the present invention, a method and device for requesting packet delay status by using an UPF event exposure service be provided.

PRIORITY

This application is a continuation of U.S. application Ser. No.17/912,267, which was filed in the U.S. Patent and Trademark Office onSep. 16, 2022, which is a National Phase Entry of PCT InternationalApplication No. PCT/KR2021/003363, which was filed on Mar. 18, 2021, andclaims priority to Korean Patent Application No. 10-2020-0035082, whichwas filed on Mar. 23, 2020, the entire content of each of which isincorporated herein by reference.

BACKGROUND 1. Field

The disclosure relates to a communication system, and more particularly,to a method and device for requesting a packet delay status using a UPFevent exposure service.

2. Description of Related Art

In order to satisfy increases in demand for wireless data traffic nowthat a 4G communication system is commercially available, efforts arebeing made to develop an enhanced 5G communication system or a pre-5Gcommunication system. Therefore, a 5G communication system or a pre-5Gcommunication system is referred to as a beyond 4G network communicationsystem or a post long term evolution (LTE) system.

In order to achieve a high data transmission rate, consideration isbeing given to implementing the 5G communication system in a mmWave band(e.g., 60 GHz band). In order to mitigate any route loss of electronicwaves in a mmWave band and to increase transmission distances ofelectronic waves, the technologies of beamforming, massive multipleinput and multiple output (MIMO), full dimensional MIMO (FD-MIMO), arrayantenna, analog beamforming, and large scale antenna are being discussedfor the 5G communication system.

Further, in order to enhance networks in the 5G communication system,the technologies of an innovative small cell, advanced small cell, cloudradio access network (cloud RAN), ultra-dense network, device to devicecommunication (D2D), wireless backhaul, moving network, cooperativecommunication, coordinated multi-points (CoMP), and interferencecancellation are being developed.

Further, hybrid frequency shift keying and quadrature amplitudemodulation (FQAM) and sliding window superposition coding (SWSC), whichare advanced coding modulation (ACM) methods; and filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA), and sparse codemultiple access (SCMA), which are advanced access technologies, arebeing developed for the 5G system.

The 5G system is considering support for various services compared tothe existing 4G system. For example, the most representative servicesmay include an enhanced mobile broad band (eMBB), ultra-reliable and lowlatency communication (URLLC), massive machine type communication(mMTC), evolved multimedia broadcast/multicast service (eMBMS), and thelike. A system providing the URLLC service may be referred to as a URLLCsystem, and a system providing the eMBB service may be referred to as aneMBB system. Further, terms service and system may be usedinterchangeably.

The URLLC service is a service newly considered in the 5G system, unlikethe existing 4G system and requires a service newly considered in the 5Gsystem, and requires ultra-high reliability (e.g., about 10-5 packeterror rate) and low latency (e.g., about 0.5 msec) requirements comparedto other services. In order to satisfy these strict requirements, theURLLC service may need to apply a shorter transmission time interval(TTI) than the eMBB service, and various operating methods are beingconsidered using this.

Innovation of Internet from a human-centered connection network in whicha human generates and consumes information to an Internet of Things(IoT) network that gives and receives and processes information to andfrom distributed constituent elements such as things has occurred.Internet of everything (IoE) technology in which big data processingtechnology through connection to a cloud server is combined with IoTtechnology has been appeared. In order to implement the IoT, technologyelements such as sensing technology, wired and wireless communicationand network infrastructure, service interface technology, and securitytechnology are required; thus, nowadays, research is being carried outon technology of a sensor network, machine to machine (M2M), and machinetype communication (MTC) for connection between things.

In an IoT environment, an intelligent Internet technology (IT) servicethat collects and analyzes data generated in connected things to providea new value to human lives may be provided. The IoT may be applied tothe field of a smart home, smart building, smart city, smart car orconnected car, smart grid, health care, smart home appliances, andhigh-tech medical service through fusion and complex connections betweenexisting information technology (IT) and various industries.

Accordingly, various attempts for applying a 5G communication system toan IoT network are being made. For example, 5G communicationtechnologies such as a sensor network, machine to machine (M2M), andmachine type communication (MTC) have been implemented by the techniqueof beamforming, MIMO, and array antenna. Application of a cloud RAN asthe foregoing big data processing technology may be an example ofconvergence of 5G technology and IoT technology.

As various services may be provided according to the above-mentioneddescription and the development of mobile communication systems, amethod for efficiently using a non-public network (NPN) is particularlyrequired.

SUMMARY

The disclosure provides a method and device for effectively providing aservice in a wireless communication system.

The technical problems to be achieved in the disclosure are not limitedto the technical problems mentioned above, and other technical problemsnot mentioned will be clearly understood by those of ordinary skill inthe art to which the disclosure belongs from the description below.

An embodiment of the disclosure proposes a method of providing packetdelay status monitoring for an URLLC service based on an UPF eventexposure service.

According to an embodiment of the disclosure, a method performed by anetwork exposure function (NEF) in a wireless communication system mayinclude receiving, from an application function (AF), a first messagerequesting registration of an event subscription service to a user planefunction (UPF); transmitting, to another network entity, a secondmessage requesting information on the UPF; receiving, from the anothernetwork entity, a third message including the information on the UPF;and transmitting, to the UPF selected based on the information on theUPF, a fourth message requesting registration of the event subscriptionservice.

Further, the second message may include at least one of a generic publicsubscription identifier (GPSI), an Internet protocol (IP) address of aterminal, a medium access control (MAC) address of the terminal, a datanetwork name (DNN), slice information, or a subscription permanentidentifier (SUPI).

Further, the another network entity may be a binding support function(BSF) or a policy control function (PCF).

Further, the method may further include receiving, from the UPF, a fifthmessage including information indicating occurrence of the subscribedevent; and transmitting, to the AF, a sixth message including theinformation indicating occurrence of the event.

Further, at least one of a case that information indicating thatinformation on the UPF is requested is included in the second message,information for identifying the UPF is included in the second message,or the second message is a preconfigured message requesting informationon the UPF, the another network entity recognizes that the secondmessage requests information on the UPF.

According to an embodiment of the disclosure, a method performed by anapplication function (AF) in a wireless communication system may includetransmitting, to a binding support function (BSF), a first messagerequesting information on a user plane function (UPF); receiving, fromthe BSF, a second message including the information on the UPF; andtransmitting, to the UPF selected based on the information on the UPF, athird message requesting registration of an event subscription service.

Further, the first message may include at least one of a generic publicsubscription identifier (GPSI), an Internet protocol (IP) address of aterminal, a medium access control (MAC) address of the terminal, a datanetwork name (DNN), slice information, or a subscription permanentidentifier (SUPI).

Further, the method may further include receiving, from the UPF, afourth message including information indicating occurrence of thesubscribed event.

According to an embodiment of the disclosure, a network exposurefunction (NEF) of a wireless communication system may include atransceiver; and a controller configured to control to receive, from anapplication function (AF) via the transceiver, a first messagerequesting registration of an event subscription service to a user planefunction (UPF), transmit, to another network entity via the transceiver,a second message requesting information on the UPF, receive, from theanother network entity via the transceiver, a third message includingthe information on the UPF, and transmit, to the UPF selected based onthe information on the UPF via the transceiver, a fourth messagerequesting registration of the event subscription service.

According to an embodiment of the disclosure, an application function(AF) of a wireless communication system may include a transceiver; and acontroller configured to control to transmit, to a binding supportfunction (BSF) via the transceiver, a first message requestinginformation on a user plane function (UPF), receive, from the BSF viathe transceiver, a second message including the information on the UPF,and transmit, to the UPF selected based on the information on the UPFvia the transceiver, a third message requesting registration of an eventsubscription service.

According to an embodiment of the disclosure, it is possible to providea device and method for effectively providing a service in a wirelesscommunication system.

The effects obtainable in the disclosure are not limited to theabove-mentioned effects, and other effects not mentioned will be clearlyunderstood by those of ordinary skill in the art to which the disclosurebelongs from the description below.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a structure of a 5G network according to anembodiment of the disclosure.

FIG. 2 illustrates a procedure for an external AF to use a packet delaystatus event exposure service according to an embodiment of thedisclosure.

FIG. 3 illustrates a procedure for an internal AF to use a packet delaystatus event exposure service according to an embodiment of thedisclosure.

FIG. 4 illustrates a procedure for an external AF to use a packet delaystatus event exposure service according to an embodiment of thedisclosure.

FIG. 5 illustrates a procedure for storing a UPF ID in order for a PCFand a BSF to search for a UPF according to an embodiment of thedisclosure.

FIG. 6 illustrates a procedure for updating a (PSA) UPF ID in a PCF anda BSF in the case that a PSA UPF is relocated according to an embodimentof the disclosure.

FIG. 7 is a block diagram illustrating a constitution of a terminalaccording to an embodiment of the disclosure.

FIG. 8 is a block diagram illustrating a constitution of a networkentity according to an embodiment of the disclosure.

DETAILED DESCRIPTION

Hereinafter, preferred embodiments of the disclosure will be describedin detail with reference to the accompanying drawings. In this case, itshould be noted that in the accompanying drawings, the same componentsare denoted by the same reference numerals if possible. Further,detailed descriptions of well-known functions and configurations thatmay obscure the gist of the disclosure will be omitted.

In describing embodiments in this specification, descriptions oftechnical contents that are well known in the technical field to whichthe disclosure pertains and that are not directly related to thedisclosure will be omitted. This is to more clearly convey the gist ofthe disclosure without obscuring the gist of the disclosure by omittingunnecessary description.

For the same reason, some components are exaggerated, omitted, orschematically illustrated in the accompanying drawings. Further, thesize of each component does not fully reflect the actual size. In eachdrawing, the same reference numerals are given to the same orcorresponding components.

Advantages and features of the disclosure, and a method of achievingthem will become apparent with reference to the embodiments describedbelow in detail in conjunction with the accompanying drawings. However,the disclosure is not limited to the embodiments disclosed below, butmay be implemented in various different forms, and only embodiments ofthe disclosure enable the disclosure to be complete, and are provided tofully inform the scope of the disclosure to those of ordinary skill inthe art to which the disclosure belongs, and the disclosure is onlydefined by the scope of the claims. Like reference numerals refer tolike components throughout the specification.

In this case, it will be understood that each block of message flowdiagrams and combinations of the message flow diagrams may be performedby computer program instructions. Because these computer programinstructions may be mounted in a processor of a general purposecomputer, special purpose computer, or other programmable dataprocessing equipment, the instructions performed by a processor of acomputer or other programmable data processing equipment generate ameans that performs functions described in the message flow diagramblock(s). Because these computer program instructions may be stored in acomputer usable or computer readable memory that may direct a computeror other programmable data processing equipment in order to implement afunction in a particular manner, the instructions stored in the computerusable or computer readable memory may produce a production articlecontaining instruction means for performing the function described inthe message flow diagram block(s). Because the computer programinstructions may be mounted on a computer or other programmable dataprocessing equipment, a series of operational steps are performed on thecomputer or other programmable data processing equipment to generate acomputer-executed process; thus, instructions for performing a computeror other programmable data processing equipment may provide steps forperforming functions described in the message flow diagram block(s).

Further, each block may represent a module, a segment, or a portion of acode including one or more executable instructions for executing aspecified logical function(s). Further, it should be noted that in somealternative implementations, functions recited in the blocks may occurout of order. For example, two blocks illustrated one after another mayin fact be performed substantially simultaneously, or the blocks may besometimes performed in the reverse order according to the correspondingfunction.

In this case, the term ‘-unit’ used in this embodiment means software orhardware components such as FPGA or ASIC, and ‘-unit’ performs certainroles. However. ‘-unit’ is not limited to software or hardware. ‘-unit’may be configured to reside in an addressable storage medium or may beconfigured to reproduce one or more processors. Therefore, as anexample, ‘-unit’ includes components such as software components,object-oriented software components, class components, and taskcomponents, processes, functions, properties, procedures, subroutines,segments of program code, drivers, firmware, microcode, circuit, data,databases, data structures, tables, arrays, and variables. Functionsprovided in the components and ‘-units’ may be combined into a smallernumber of components and ‘-units’ or may be further separated intoadditional components and ‘-units’. Further, components and ‘-units’ maybe implemented to reproduce one or more CPUs in a device or securemultimedia card.

Hereinafter, the base station is a subject performing resourceallocation of the terminal and may be at least one of a node B, basestation (BS), eNode B (eNode B), gNB (gNode B), radio access unit, basestation controller, or a node on the network. The terminal may include auser equipment (UE), a mobile station (MS), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing acommunication function. Further, the embodiment of the disclosure may beapplied to other communication systems having a similar technicalbackground or channel type to the embodiment of the disclosure describedbelow. Further, the embodiments of the disclosure may be applied toother communication systems through some modifications within a rangethat does not significantly depart from the scope of the disclosure asdetermined by a person having skilled technical knowledge.

A term for identifying an access node used in the following description,a term referring to a network entity or a network function (NF), a termreferring to messages, a term referring to an interface between networkobjects, and terms referring to various identification information areexemplified for convenience of description. Accordingly, the disclosureis not limited to the terms described below, and other terms referringto objects having equivalent technical meanings may be used.

Hereinafter, for convenience of description, some terms and namesdefined in the 3rd generation partnership project long term evolution(3GPP) standard may be used. However, the disclosure is not limited bythe above terms and names, and may be equally applied to systemsconforming to other standards.

Embodiments of the disclosure provide a method in which anexternal/internal application function (AF) 160 in a 5G core (5GC) mayuse a packet delay status service provided to a user plane function(UPF) event exposure service using a service-based interface (SBI).

FIG. 1 illustrates a structure of a 5G network according to anembodiment of the disclosure.

With reference to FIG. 1 , descriptions of network entities or networknodes constituting a 5G network are as follows.

An (radio) access network ((R)AN) 115 is a subject that performs radioresource allocation of a terminal 110 and may be an at least one of aneNode B, a node B, a base station (BS), a next generation radio accessnetwork (NG-RAN), a 5G-AN, a radio access unit, a base stationcontroller, or a node on a network. The terminal 110 may include a userequipment (UE), a next generation UE (NG UE), a mobile station (MS), acellular phone, a smart phone, a computer, or a multimedia systemcapable of performing a communication function.

Hereinafter, although the embodiment of the disclosure is described bytaking the 5G system as an example, the embodiment of the disclosure maybe applied to other communication systems having a similar technicalbackground. Further, the embodiments of the disclosure may be applied toother communication systems through some modifications within a rangethat does not significantly depart from the scope of the disclosure asdetermined by a person having skilled technical knowledge.

The wireless communication system defines a next generation (gen) core(NG core) or a 5G core network (5GC), which is a new core network as itevolves from a 4G system to a 5G system. The new core networkvirtualized all the existing network entities (NEs) and made it into anetwork function (NF). According to an embodiment of the disclosure, anetwork function may mean a network entity, a network component, and anetwork resource.

According to an embodiment of the disclosure, a 5GC may include NFsillustrated in FIG. 1 . The 5GC is not limited to an example of FIG. 1and may include a larger number of NFs or a smaller number of NFs thanthat illustrated in FIG. 1 .

According to an embodiment of the disclosure, an access and mobilitymanagement function (AMF) 120 may be a network function for managing themobility of the terminal 110.

According to an embodiment of the disclosure, a session managementfunction (SMF) 130 may be a network function for managing a packet datanetwork (PDN) connection provided to the terminal 110. The PDNconnection may be referred to as a protocol data unit (PDU) session.

According to an embodiment of the disclosure, a policy control function(PCF) 150 may be a network function that applies a service policy of amobile communication operator to a terminal, a charging policy, and apolicy for a PDU session.

According to an embodiment of the disclosure, unified data management(UDM) 155 may be a network function for storing information on asubscriber.

According to an embodiment of the disclosure, a network exposurefunction (NEF) 140 may be a function of providing information on theterminal to a server outside the 5G network.

Further, the NEF 140 may provide a function of providing informationnecessary for providing a service to the 5G network and storing theinformation in a user data repository (UDR) (not illustrated).

According to an embodiment of the disclosure, a user plane function(UPF) 125 may be a function that serves as a gateway for transferringuser data (PDU) to a data network (DN) 175.

In particular, in the disclosure. Nupf, which is an SBI interface, isdefined to the UPF 125, thereby providing an event exposure service toother NFs.

According to an embodiment of the disclosure, a network repositoryfunction (NRF) 145 may perform a function of discovering the NF.

According to an embodiment of the disclosure, an authentication serverfunction (AUSF) 165 may perform terminal authentication in a 3GPP accessnetwork and a non-3GPP access network.

According to an embodiment of the disclosure, a network slice selectionfunction (NSSF) 135 may perform a function of selecting a network sliceinstance provided to the terminal 140.

According to an embodiment of the disclosure, a service communicationproxy (SCP) 170 may provide an indirect communication method thatsubstitutes for service search, call, response, and the like ininterworking between NFs.

According to an embodiment of the disclosure, the DN 175 may be a datanetwork in which the terminal 110 transmits and receives data in orderto use a service of a network provider or a 3rd party service.

FIG. 2 illustrates a procedure for an external AF to use a packet delaystatus event exposure service according to an embodiment of thedisclosure.

With reference to FIG. 2 , in step 210, in order to subscribe or cancela subscription to a packet delay status event exposure service, an AF201 may transmit a service subscription request or cancellation message(Nnef_EventExposure_Subscribe/Unsubscribe request) to an NEF 203. Inorder to cancel a subscription, a subscription correlation ID thatidentifies the existing event service subscription should be senttogether. The subscription request message may include at least one ofthe following parameters.

-   -   Event ID(s)        -   Packet Delay Status (PDS)    -   Target of Event Reporting        -   It may be any combination of a generic public subscription            identifier (GPSI), external group identifier, UE IP address            (IPv4 address or IPv6 prefix), UE medium access control            (MAC) address, AF-Service-Identifier. or data network name            (DNN)/S-NSSAI (network slice selection assistance            information) combination information.        -   QoS Flow Detection Information (Traffic Descriptor            Information)        -   Source address: UE IP address(IPv4 address or IPv6 prefix),            UE MAC address            -   Destination address: Server IP address(IPv4 address or                IPv6 prefix). UE MAC address        -   Source(UE) port number        -   Destination(Server) port number        -   Protocol ID (IPv4) or Next Header type (IPv6)        -   Flow Label(IPv6)            -   Ethertype(Ethernet)    -   Event Reporting Information        -   Event reporting mode            -   Periodic, one time, on event detection        -   Immediate reporting flag        -   Minimum waiting time if reporting frequency: event detection    -   Notification Target Address(+Notification Correlation ID)        -   AF ID(address), NEF ID(address)    -   Event Filter Information        -   Reporting frequency: event detection            -   Event Parameter Type1 (Event Parameter Value1)            -   DL packet delay (threshold of the DL packet delay)            -   Event Parameter Type2 (Event Parameter Value2)            -   UL packet delay (threshold of the UL packet delay)            -   Event Parameter Type1 (Event Parameter Value1)            -   Round trip packet delay (threshold of the round trip                packet delay)        -   Reporting frequency: periodic            -   Event Parameter Type1 (Event Parameter Value1)            -   DL packet delay (reporting time period)            -   Event Parameter Type2 (Event Parameter Value2)            -   UL packet delay (reporting time period)            -   Event Parameter Type1 (Event Parameter Value1)            -   Round trip packet delay (reporting time period)        -   Reporting frequency: one time            -   Event Parameter Type1 (Event Parameter Value1)    -   DL packet delay (PDU Session is released)    -   Event Parameter Type2 (Event Parameter Value2)    -   UL packet delay (PDU Session is released)    -   Event Parameter Type1 (Event Parameter Value1)    -   Round trip packet delay (PDU Session is released)    -   Expiry time    -   The time up to which the subscription is desired to be kept as        active

In step 220, in order to find a UPF through which a specific servicedata flow (SDF) or packet flow passes, the NEF 203 may transmit anNbsf_Management_Discovery request message to a binding support function(BSF) 205. The operation provides a search for a PCF or an UPF in chargeof a specific PDU session. An input value may be a combination of an UEIP address (IPv4 address or IPv6 prefix), an UE MAC address. DNN, DNinformation (e.g., S-NSSAI), subscription permanent identifier (SUPI),GPSI, and the like. In step 210, when the NEF 203 receives anAF-service-identifier as a target of event reporting value, the NEF 203may change the AF-service-identifier to a DNN/S-NSSAI combination.Further, in order to designate a discovering NF to be searched, (PCF orUPF) may be designated as an input value of the function. Alternatively,in the case that the Nbsf_Management_Discovery request message includesinformation that may use for identifying the UPF, theNbsf_Management_Discovery request message is a message requestinginformation on the UPF (e.g., UPF ID), and the BSF that has receivedthis may recognize it. Another method is to differentiate thediscovering NF to change a name of a service operation. That is, whensearching for the UPF, the Nbsf_management_Discovery_UPF request (GPSI,UE IP address) service operation is used, and when searching for a PCF,an Nbsf_management_Discovery_PCF request (GPSI, UE IP address) is used.Another method is to differentiate the search target NF using a “TYPE”parameter. For example, there may be a method in which TYPE1 is definedas a PCF. TYPE2 is defined as a UPF, and TYPE3 is defined when both aPCF and a UPF are searched at the same time. For example, when searchingfor a UPF, it is used as in an Nbsf_management_Discovery_Request (GPSI,UE IP address. TYPE2). When the NEF 203 receives an external groupidentifier as an input value in step 210, the NEF 203 may search for allUPFs in charge of all UEs belonging to the group and send a servicesubscription request.

In step 230, the BSF 205 may transmit identification information (e.g.,ID of a UPF 207) of the UPF 207 requested to search using the GPSI andthe UE IP address to the NEF 203 through the Nbsf_management_Discoveryresponse message. In order to search for the UPF 207, the NEF 203 mayuse any combination of a UE IP address (IPv4 address or IPv6 prefix), UEMAC address, AF-service-identifier. DNN. DN information (e.g., S-NSSAI),SUPI, or GPSI values.

In step 240, in order to subscribe or cancel a subscription to thepacket delay status event exposure service, the NEF 203 may transmit aservice subscription request or cancellation message(Nupf_EventExposure_Subscribe/Unsubscribe request) to the UPF 207. Inorder for the NEF 203 to cancel a subscription, the NEF 203 may sendtogether a subscription correlation ID identifying an existing eventservice subscription to the UPF 207. When the NEF 203 receives anAF-service-identifier as the target of event reporting value in step210, the NEF 203 may change the AF-service-identifier to a DNN/S-NSSAIcombination. The NEF 203 may add an address thereof to the notificationtarget address and information received from the AF 201 in step 210 andtransmit it to the UPF 207. This is for the NEF 203 to receive anotification on a change when a change of information subscribed to theUPF 207 occurs. When the service subscription is authorized by the UPF207, the UPF 207 may store the event trigger and the identity of therequester.

The UPF 207 may perform a packet delay status event exposure service fora specific QoS flow of a specific UE through target of event reportinginformation. The specific QoS flow may be specified through trafficdetection information in target of event reporting information. The UPF207 may report to an event exposure service subscriber at an eventdetection/periodic/one time period according to the reporting frequencyin event filter information. The UPF 207 may report the DL packetdelay/UL packet delay/round trip packet delay value to the subscriberevery corresponding period. The event detection period may be notifiedto the subscriber when the packet delay is a threshold or more. Theperiodic period may be reported to the subscriber at every reportingtime period interval. One time period may be reported to the subscriberwhen a PDU session in which the corresponding QoS flow flows isreleased. Event reporting information may include an event reportingmode and include an immediate reporting flag indicating whether toimmediately send reporting to the subscriber. A minimum waiting time ifreporting frequency indicates a time value to wait until at least thenext report after detecting an event and reporting it to the subscriberin the event detection period. This is to prevent frequent reports dueto events occurring too frequently.

The UPF 207 may measure the DL, UL and round trip packet delay of an N3interface with the NG-RAN in order to measure the packet delay for aspecific QoS flow, and the packet delay between the UE and the NG-RANmay be measured by requesting to the NG-RAN.

In step 250, the UPF 207 may transmit aNupf_EventExposure_Subscribe/Unsubscribe response message to the NEF 203in response to a subscription or cancellation of a subscription to theservice. The message may include a subscription correlation ID and anexpiry time.

In step 260, the NEF 203 may transmit aNnef_EventExposure_Subscribe/Unsubscribe response message to the AF 201in response to a subscription or cancellation of a subscription to theservice. The message may include a subscription correlation ID and anexpiry time.

In step 270, the UPF 207 may detect occurrence of an event and transmitthe event report together with a time stamp to the NEF 203 through aNupf_EventExposure_Notify message.

The NEF 203 may store event report information together with the timestamp in a UDR (not illustrated) using a Nudr_DM_Create orNudr_DM_Update message.

In step 280, the NEF 203 may transmit the received event report to theAF 201 through Nnef_EventExposure_Notify.

FIG. 3 illustrates a procedure for an internal AF to use a packet delaystatus event exposure service according to an embodiment of thedisclosure.

The embodiment illustrated in FIG. 3 is similar to the procedure of theembodiment illustrated in FIG. 2 , except that the NEF 203 is not usedfor subscribing to a packet delay status event exposure service becausean AF 301 is in a network.

With reference to FIG. 3 , in step 310, in order to find a UPF throughwhich a specific SDF or packet flow passes, the AF 301 may transmit anNbsf_Management_Discovery request message to a binding support function(BSF) 303. The operation provides a search for a PCF or a UPF in chargeof a specific PDU session. An input value may be a combination of an UEIP address (IPv4 address or IPv6 prefix), an UE MAC address, a DNN. DNinformation (e.g., S-NSSAI). SUPI, GPSI, and the like. Further, in orderto designate a discovering NF to be searched. (PCF or UPF) may bedesignated as an input value of the function. Another method may be todifferentiate the discovering NF to change the name of the serviceoperation. That is, there may be a method of using anNbsf_management_Discovery_UPF request (GPSI, UE IP address) serviceoperation when searching for the UPF and using anNbsf_management_Discovery_PCF request (GPSI, UE IP address) whensearching for the PCF.

As another method, there may be a method of differentiating a searchtarget NF using a “TYPE” parameter. For example, TYPE1 may be defined asthe PCF. TYPE2 may be defined as the UPF, and TYPE3 may be defined whenboth the PCF and the UPF are searched at the same time.

For example, when searching for the UPF, it may be used as inNbsf_management_Discovery_Request (GPSI, UE IP address. TYPE2).

In step 320, the BSF 303 may transmit the identification information(e.g., ID of a UPF 305) of the UPF 305 requested to search using theGPSI and the UE IP address to the AF 301 through theNbsf_management_Discovery response message. In order to search for theUPF 305, the AF 301 may use any combination of a UE IP address (IPv4address or IPv6 prefix), UE MAC address, AF-Service-Identifier, DNN, DNinformation (e.g., S-NSSAI), SUPI, or GPSI values.

In step 340, in order to subscribe or unsubscribe to the packet delaystatus event exposure service, the AF 301 may transmit a servicesubscription request or cancellation message(Nupf_EventExposure_Subscribe/Unsubscribe request) to the UPF 305. Inorder to cancel a subscription, the AF 301 may send a subscriptioncorrelation ID that identifies an existing event service subscriptiontogether with the service subscription cancellation message to the UPF305. When the service subscription is authorized by the UPF 305, the UPF305 may store the event trigger and the identity of the requester. Thesubscription request message may include at least one of the followingparameters.

-   -   Event ID(s)    -   Packet Delay Status (PDS)    -   Target of Event Reporting    -   It may be any combination of a generic public subscription        identifier (GPSI), external group identifier. UE IP address        (IPv4 address or IPv6 prefix), UE MAC address.        AF-Service-Identifier, or DNN/S-NSSAI combination information.    -   QoS Flow Detection Information (Traffic Descriptor Information)    -   Source address: UE IP address(IPv4 address or IPv6 prefix). UE        MAC address    -   Destination address: Server IP address(IPv4 address or IPv6        prefix), UE MAC address    -   Source(UE) port number    -   Destination(Server) port number    -   Protocol ID (IPv4) or Next Header type (IPv6)    -   Flow Label(IPv6)    -   Ethertype(Ethernet)    -   Event Reporting Information    -   Event reporting mode    -   Periodic, one time, on event detection    -   Immediate reporting flag    -   Minimum waiting time if reporting frequency: event detection    -   Notification Target Address(+Notification Correlation ID)    -   AF ID(address), NEF ID(address)    -   Event Filter Information    -   Reporting frequency: event detection    -   Event Parameter Type1 (Event Parameter Value1)    -   DL packet delay (threshold of the DL packet delay)    -   Event Parameter Type2 (Event Parameter Value2)    -   UL packet delay (threshold of the UL packet delay)    -   Event Parameter Type1 (Event Parameter Value1)    -   Round trip packet delay (threshold of the round trip packet        delay)    -   Reporting frequency: periodic    -   Event Parameter Type1 (Event Parameter Value1)    -   DL packet delay (reporting time period)    -   Event Parameter Type2 (Event Parameter Value2)    -   UL packet delay (reporting time period)    -   Event Parameter Type1 (Event Parameter Value1)    -   Round trip packet delay (reporting time period)    -   Reporting frequency: one time    -   Event Parameter Type1 (Event Parameter Value1)    -   DL packet delay (PDU Session is released)    -   Event Parameter Type2 (Event Parameter Value2)    -   UL packet delay (PDU Session is released)    -   Event Parameter Type1 (Event Parameter Value1)    -   Round trip packet delay (PDU Session is released)    -   Expiry time    -   The time up to which the subscription is desired to be kept as        active

The UPF 305 may perform a packet delay status event exposure service fora specific QoS flow of a specific UE through target of event reportinginformation. The specific QoS flow may be specified through trafficdetection information in target of event reporting information. The UPF305 may report to the event exposure service subscriber at an eventdetection/periodic/one time period according to the reporting frequencyin the event filter information. The UPF 305 may report the DL packetdelay/UL packet delay/round trip packet delay value to the subscriberevery corresponding period. The event detection period may be notifiedto the subscriber when the packet delay is a threshold or more. Theperiodic period may be reported to the subscriber at every reportingtime period interval. One time period may be reported to the subscriberwhen a PDU session in which the corresponding QoS flow flows isreleased. Event reporting information may include an event reportingmode and include an immediate reporting flag indicating whether toimmediately send reporting to the subscriber. A minimum waiting time ifreporting frequency indicates a time value to wait until at least thenext report after detecting an event and reporting it to the subscriberin the event detection period. This is to prevent frequent reports dueto events occurring too frequently.

The UPF 305 may measure DL. UL, and round trip packet delay of an N3Interface with the NG-RAN in order to measure packet delay for aspecific QoS flow, and packet delay between the UE and the NG-RAN may bemeasured by requesting to the NG-RAN.

In step 340, the UPF 305 may transmit aNupf_EventExposure_Subscribe/Unsubscribe response message to the AF 301in response to a subscription or cancellation of a subscription to aservice. The message may include a subscription correlation ID and anexpiry time.

In step 350, the UPF 305 may detect occurrence of an event and transmitthe event report together with a time stamp to the AF 301 through aNupf_EventExposure_Notify message.

FIG. 4 illustrates a procedure for an external AF to use a packet delaystatus event exposure service according to an embodiment of thedisclosure.

All procedures of the embodiment illustrated in FIG. 4 are basically thesame as those in FIG. 2 , but are different from those in FIG. 2 in thatthe PCF instead of the BSF is used for searching for the UPF. That is,the embodiment of FIG. 4 is similar to the embodiment illustrated inFIG. 2 except for steps 420 and 430.

With reference to FIG. 4 , in step 410, in order to subscribe or cancela subscription to a packet delay status event exposure service, an AF401 may transmit a service subscription request or cancellation message(Nnef_EventExposure_Subscribe/Unsubscribe request) to an NEF 403. Inorder to cancel a subscription, a subscription correlation ID thatidentifies the existing event service subscription should be senttogether. The subscription request message may include at least one ofthe following parameters.

-   -   Event ID(s)    -   Packet Delay Status (PDS)    -   Target of Event Reporting    -   It may be any combination of a generic public subscription        identifier (GPSI), external group identifier, UE IP address        (IPv4 address or IPv6 prefix). UE MAC address.        AF-Service-Identifier, and DNN/S-NSSAI combination information.    -   QoS Flow Detection Information (Traffic Descriptor Information)    -   Source address: UE IP address(IPv4 address or IPv6 prefix), UE        MAC address    -   Destination address: Server IP address(IPv4 address or IPv6        prefix). UE MAC address    -   Source(UE) port number    -   Destination(Server) port number    -   Protocol ID (IPv4) or Next Header type (IPv6)    -   Flow Label(IPv6)    -   Ethertype(Ethernet)    -   Event Reporting Information    -   Event reporting mode    -   Periodic, one time, on event detection    -   Immediate reporting flag    -   Minimum waiting time if reporting frequency: event detection    -   Notification Target Address(+Notification Correlation ID)    -   AF ID(address), NEF ID(address)    -   Event Filter Information    -   Reporting frequency: event detection    -   Event Parameter Type1 (Event Parameter Value1)    -   DL packet delay (threshold of the DL packet delay)    -   Event Parameter Type2 (Event Parameter Value2)    -   UL packet delay (threshold of the UL packet delay)    -   Event Parameter Type1 (Event Parameter Value1)    -   Round trip packet delay (threshold of the round trip packet        delay)    -   Reporting frequency: periodic    -   Event Parameter Type1 (Event Parameter Value1)    -   DL packet delay (reporting time period)    -   Event Parameter Type2 (Event Parameter Value2)    -   UL packet delay (reporting time period)    -   Event Parameter Type1 (Event Parameter Value1)    -   Round trip packet delay (reporting time period)    -   Reporting frequency: one time    -   Event Parameter Type1 (Event Parameter Value1)    -   DL packet delay (PDU Session is released)    -   Event Parameter Type2 (Event Parameter Value2)    -   UL packet delay (PDU Session is released)    -   Event Parameter Type1 (Event Parameter Value1)    -   Round trip packet delay (PDU Session is released)    -   Expiry time    -   The time up to which the subscription is desired to be kept as        active

In step 420, in order to find a UPF through which a specific SDF orpacket flow passes, the NEF 403 may transmit anNpcf_Management_Discovery request message to a policy control function(PCF) 405. The operation provides a search for a UPF 407 in charge of aspecific PDU session. An input value may be a combination of an UE IPaddress (IPv4 address or IPv6 prefix), an UE MAC address, a DNN, DNinformation (e.g., S-NSSAI), SUPI, GPSI, and the like. In step 410, whenthe NEF 403 receives an AF-Service-Identifier as a target of eventreporting value, the NEF 403 may change the AF-Service-Identifier to aDNN/S-NSSAI combination. When the NEF 403 receives the external groupidentifier as an input value in step 410, the NEF 403 may search for allUPFs in charge of all UEs belonging to a group and send a servicesubscription request.

In step 430, the PCF 405 may transmit the identification information(e.g., the ID of the UPF 407) of the UPF 407 requested to search usingthe GPSI and the UE IP address to the NEF 403 through theNpcf_management_Discovery response message. In order to search for theUPF 407, the NEF 403 may use any combination of an UE IP address (IPv4address or IPv6 prefix), an UE MAC address, an AF-Service-Identifier, aDNN. DN information (e.g., S-NSSAI), SUPI, or GPSI values.

In step 440, in order to subscribe or cancel a subscription to thepacket delay status event exposure service, the NEF 403 may transmit aservice subscription request or cancellation message(Nupf_EventExposure_Subscribe/Unsubscribe request) to the UPF 407. Inorder for the NEF 403 to cancel a subscription, the NEF 403 may transmittogether a subscription correlation ID identifying an existing eventservice subscription to the UPF 407. When the NEF 403 receives anAF-Service-Identifier as a target of event reporting value in step 410,the NEF 403 may change the AF-Service-Identifier to a DNN/S-NSSAIcombination. The NEF 403 may add an address thereof to the informationreceived from the AF 401 and notification target address in step 410 andtransmit it to the UPF 407. This is for the NEF 403 to receive anotification of a change when a change occurs in information subscribedto the UPF 407. When the service subscription is authorized by the UPF407, the UPF 407 may store the event trigger and the identity of therequester.

The UPF 407 may perform a packet delay status event exposure service fora specific QoS flow of a specific UE through target of event reportinginformation. The specific QoS flow may be specified through trafficdetection information in target of event reporting information. The UPF407 may report to the event exposure service subscriber at an eventdetection/periodic/one time period according to the reporting frequencyin the event filter information. The UPF 407 may report a DL packetdelay/UL packet delay/round trip packet delay value to the subscriberevery corresponding period. The event detection period may be notifiedto the subscriber when the packet delay is a threshold or more. Theperiodic period may be reported to the subscriber at every reportingtime period interval. One time period may be reported to the subscriberwhen a PDU session in which the corresponding QoS flow flows isreleased. Event reporting information may include an event reportingmode and include an immediate reporting flag indicating whether toimmediately send reporting to the subscriber. A minimum waiting time ifreporting frequency indicates a time value to wait until at least thenext report after detecting an event and reporting it to the subscriberin an event detection period. This is to prevent frequent reports due toevents occurring too frequently.

The UPF 407 may measure the DL. UL, and round trip packet delay of an N3interface with the NG-RAN in order to measure the packet delay for aspecific QoS flow, and the packet delay between the UE and the NG-RANmay be measured by requesting to the NG-RAN.

In step 450, the UPF 407 may transmit aNupf_EventExposure_Subscribe/Unsubscribe response message to the NEF 403in response to a subscription or cancellation of a subscription to aservice. The message may include a subscription correlation ID and anexpiry time.

In step 460, the NEF 403 may transmit anNnef_EventExposure_Subscribe/Unsubscribe response message to the AF 401in response to a subscription or cancellation of a subscription to aservice. The message may include a subscription correlation ID and anexpiry time.

In step 470, the UPF 407 may detect occurrence of an event to transmitthe event report together with a time stamp to the NEF 403 through aNupf_EventExposure_Notify message.

The NEF 403 may store event report information together with a timestamp in a UDR (not illustrated) using a Nudr_DM_Create orNudr_DM_Update message.

In step 480, the NEF 403 may transmit the received event report to theAF 401 through Nnef_EventExposure_Notify.

FIG. 5 illustrates a procedure for storing a UPF ID in order for a PCFand a BSF to search for a UPF according to an embodiment of thedisclosure.

The procedure of the embodiment illustrated in FIG. 5 may be performedby an SMF initiated SM policy association modification procedureperformed during a PDU session establishment procedure.

With reference to FIG. 5 , in step 510, a PDU session establishmentprocedure may be performed between an SMF 501, a PCF 503, and a BSF 505.

In step 520, in order to update the SM policy association of thegenerated PDU session, the SMF 501 transmits anNpcf_SMPolicyControl_Update request message to the PCF 503. Parametersincluded in the message may include at least one of an SM policyassociation ID. IPv4 address and/or IPv6 network prefix, user locationinformation. UE time zone, serving network. RAT type, session AMBR, orsubscribed default QoS information, DN authorization profile index, MACaddress, port number of manageable Ethernet port, UE-DS-TT residencetime and port management information container, MA PDU requestindication, or MA PDU network-upgrade allowed indication. In particular,the SMF 501 may add a (PSA) UPF ID and a (PSA) UPF address in charge ofthe corresponding PDU session to the message and transmit the message tothe PCF 503. Thereby, the PCF 503 may store the UPF ID and UPF addressin charge of the generated PDU session.

In step 530, the PCF 503 may transmit an Npcf_SMPolicyControl_Updateresponse message to the SMF 501 in response to theNpcf_SMPolicyControl_Update request message.

In step 540, the PCF 503 may register PDU session related information tothe BSF 505 through the Nbsf_Management_Register request message. Theregistration information may include at least one of an UE address(es),SUPI. GPSI, DNN, DN information (e.g., S-NSSAI), PCF address(es), PCFid, or PCF set ID. In order to register UPF information in the BSF 505,the PCF 503 may additionally provide the UPF address (es) and the UPF idto the BSF 505. Thereby, the BSF 505 may store the UPF ID and UPFaddress in charge of the generated PDU session.

In step 550, the BSF 503 may transmit an Nbsf_Management_Registerresponse message to the PCF 503 in response to theNbsf_Management_Register request message.

FIG. 6 illustrates a procedure for updating a (PSA) UPF ID in a PCF anda BSF in the case that a PSA UPF is relocated according to an embodimentof the disclosure.

With reference to FIG. 6 , in step 610, the PSA UPF may be relocated.

In step 620, after the PSA UPF is relocated, in order to update the SMpolicy association of a PDU session, an SMF 601 may transmit anNpcf_SMPolicyControl_Update request message to a PCF 603. Parametersincluded in the message may include at least one of an SM policyassociation ID, IPv4 address and/or IPv6 network prefix, user locationinformation, UE time zone, serving network, RAT type, session AMBR, orsubscribed default QoS information, DN authorization profile index. MACaddress, port number of manageable Ethernet port, UE-DS-TT residencetime and port management information container, MA PDU requestindication, or MA PDU network-upgrade allowed indication. In particular,the SMF 601 may add the (PSA) UPF ID and (PSA) UPF address changed byPSA UPF relocation to the message to transmit the message to the PCF603. Thereby, the PCF 603 may store the UPF ID and UPF address changedby the PSA UPF relocation.

In step 630, the PCF 603 may transmit an Npcf_SMPolicyControl_Updateresponse message to the SMF 601 in response to theNpcf_SMPolicyControl_Update request message.

In step 640, the PCF 603 may update the PDU session related informationto a BSF 605 through the Nbsf_Management_Update request message.Parameters included in the message may include at least one of a bindingidentifier for a PDU session, a UE address(es), or a PCF id. In order toupdate the UPF information to the BSF 605, the PCF 603 may additionallyprovide an UPF address (es) and an UPF id to the BSF 605. Thereby, theBSF 605 may store the UPF ID and UPF address changed by PSA UPFrelocation.

In step 550, the BSF 605 may transmit an Nbsf_Management_Registerresponse message to the PCF 603 in response to theNbsf_Management_Update request message.

Hereinafter, the event exposure service parameters that should be addedto support the packet delay status event exposure service will bedescribed.

TABLE 1 Enumeration UpfEvent Enumeration value Description ApplicabilityPDS Packet Delay Status PacketDelayStatus

[Table 1] adds a PDS, which is a new event ID to a UPF event table forthe packet delay status event.

TABLE 2 Definition of type NupfEventExposure Attribute Data Cardi-Applic- name type P nality Description ability Supi Supi C 0 . . . 1Subscription Permanent Identifier (NOTE) Gpsi Gpsi C 0 . . . 1 GenericPublic Subscription Identifier (NOTE) anyUe boolean C 0 . . . 1 This IEshall be Ind present if the event subscription is applicable to any UE.Default value ″FALSE″ is used, if not present (NOTE) groupId GroupId C 0. . . 1 Identifies a group of UEs. (NOTE) pduSeId PduSessionId C 0 . . .1 PDU session ID (NOTE) maxWait DateTime C 0.1 Maximum wait time PacketTime after reporting Delay Status

[Table 2] adds a maxWaitTime, which is a new type for the packet delaystatus event to a type definition table.

TABLE 3 Type EventSubscription Attribute Cardi- Applic- name Data type Pnality Description ability event SmfEvent M 1 Subscribed events dnaiChDnai C 0 . . . 1 For event UP path Type Change change, this Typeattribute indicates whether the subscription is for early, late, orearly and late DNAI change notification shall be supplied. dddTraDesDddTraffic C 0 . . . 1 The traffic Downlink Descriptor descriptor Dataof the down- Delivery link data source. Status May be included for event″downlink data delivery status″. dddStati array C 1 . . . N May beincluded Downlink (DddStatus) for event ″downlink Data data deliveryDelivery status″. The Status subscribed stati (discarded, transmitted,buffered) for the event. If omitted all stati are subscribed. pdsTraDesPdsTraffic C The traffic Packet Descirptor descriptor of the Delaytarget QoS Flow. Status pdsNotEve PdsTraffic C For which Event PacketDescirptor Item is needed Delay for detection. Status pdsNotThr Notifi-C Frequency for Packet cation_ Event detection Delay threshold Status

[Table 3] adds PdsTrafficDescirptor, PdsTrafficDescirptor, andNotification_threshold types, which are new EventSubscription types fora packet delay status event.

TABLE 4 Enumeration NotificationMethod_PDS Enumeration Applic- valueDescription ability PERIODIC The notification is periodically sent.PDU_SESSION_ The notification is only sent when RELEASE PDU Session isreleased ON_EVENT_ The notification is sent each time the DETECTIONevent is detected.

TABLE 5 Enumeration NotificationEventItem Enumeration Applic- valueDescription ability DL_PACKET_ Downlink packet delay between DELAY UEand PSA UPF UP_PACKET_ Uplink packet delay between DELAY UE and PSA UPFROUND_TRIP_ Round trip packet delay between DELAY UE and PSA UPF

TABLE 6 Enumeration Notification_threshold Applic- Enumeration valueDescription ability DL_PACKET_ Threshold for Downlink DELAY_thresholdpacket delay UP_PACKET_ Threshold for Uplink DELAY_threshold packetdelay ROUND_TRIP_ Threshold Round trip DELAY_threshold packet delay

[Table 4], [Table 5], and [Table 6] define a new enumeration type forevent filter information (frequency and event items) of a packet delaystatus event.

TABLE 7 Definition of type PdsTrafficDescriptor Attribute Data Cardi-Applic- name type P nality Description ability ipv4Addr Ipv4Addr C 0 . .. 1 Ipv4 address Packet of the source Delay (UE IP address) Statusipv6Addr Ipv6Addr C 0 . . . 1 Ipv6 address Packet of the source Delay(UE IP address) Status port Uinteger O 0 . . . 1 Port number of thePacket of the source (UE) Delay Status ipv4Addr Ipv4Addr C 0 . . . 1Ipv4 address of the Packet destination (Server) Delay Status ipv6AddrIpv6Addr C 0 . . . 1 Ipv6 address of the Packet destination (Server)Delay Status port Uinteger O 0 . . . 1 Port number of the of Packetdestination (Server) Delay Status Protocol Packet ID Delay Status NOTE:At least one of the ″ipv4Addr″ attribute or the ″ipv6Addr″ attributeshall be included.

[Table 7] defines a PdsTrafficDescriptor type for the packet delaystatus event. Through the information, the UPF may search for specificQoS flow.

TABLE 8 Nupf_EventExposure specific Data Types Section Applic- Data typedefined Description ability PdsTraffic x.x.x.x Traffic descriptor ofPacketDelay Descirptor the target QOS Flow Status Notification x.x.x.xNotification PacketDelay EventItem Event Item Status Notification_x.x.x.x Threshold value PacketDelay threshold for frequency Status(event detection)

[Table 8] defines newly defined data types for a packet delay statusevent.

TABLE 9 Definition of type EventNotification Attribute Data Cardi-Applic- name type P nality Description ability event SmfEvent M 1 Eventthat is notified. time DateTime M 1 Time at which the Stamp event isobserved. supi Supi C 0 . . . 1 Subscription Permanent Identifier. It isincluded when the subscription applies to a group of UE(s) or any UE.gpsi Gpsi C 0 . . . 1 Identifies a GPSI. It shall contain an MSISDN. Itis included when it is available and the subscription applies to a groupof UE(s) or any UE. source Dnai C 0 . . . 1 Source DN Access DnaiIdentifier. Shall be included for event ″UP_PATH_CH″ if the DNAI changed(NOTE 1, NOTE 2). target Dnai C 0 . . . 1 Target DN Access DnaiIdentifier. Shall be included for event ″UP_PATH_CH″ if the DNAI changed(NOTE 1, NOTE 2). dnaiChg Dnai C 0 . . . 1 DNAI Change Type Change Type.Shall be Type included for event ″UP_PATH_CH″. sourceUe Ipv4Addr 0 0 . .. 1 The IPV4 Address of Ipv4Addr the served UE for the source DNAI. Maybe included for event ″UP_PATH_CH″. dlPacket DateTime C 0 . . . 1Downlink Packet Packet Delay Delay time Delay between UE and PSA UPF.Shall be Status included for event ″PDS″ if DLPacketDelay is requestedulPacket DateTime C 0 . . . 1 Uplink Packet Delay Packet Delay timebetween UE Delay and PSA UPF. Status Shall be included for event ″PDS″if ULPacketDelay is requested. roundtrip DateTime C 0 . . . 1 RoundTripPacket Packet Packet Delay Delay Delay time between Status UE and PSAUPF. Shall be included for event ″PDS″ if RoundTrip PacketDelay isrequested.

[Table 9] defines newly defined EventNotification types for a packetdelay status event. FIG. 7 is a block diagram illustrating aconstitution of a terminal according to an embodiment of the disclosure.

With reference to FIG. 8 , the terminal according to an embodiment ofthe disclosure may include a transceiver 710 and a controller 710 forcontrolling overall operations thereof. The transceiver 710 may includea transmitter and a receiver. The terminal may include a storage 730.

The transceiver 710 may transmit and receive signals to and from othernetwork entities.

The storage 730 may store various types of information such asinformation for an operation of the terminal and information receivedfrom other network entities.

The controller 720 may control the terminal to perform any one operationof the above-described embodiments. The controller 720 and thetransceiver 710 do not necessarily have to be implemented into separatemodules, and may be implemented into a single component in the form of asingle chip. The controller 720 and the transceiver 710 may beelectrically connected. For example, the controller 720 may be acircuit, an application-specific circuit, or at least one processor.Further, operations of the terminal may be realized by providing thememory device 730 storing the corresponding program code in an arbitrarycomponent in the terminal.

FIG. 8 is a block diagram illustrating a constitution of a networkentity according to an embodiment of the disclosure.

The network entity of the disclosure is a concept including a networkfunction according to a system implementation.

With reference to FIG. 8 , a network entity according to an embodimentof the disclosure may include a transceiver 810 and a controller 820 forcontrolling overall operations of the network entity. The transceiver810 may include a transmitter and a receiver. The network entity mayinclude a storage 830.

The transceiver 810 may transmit and receive signals to and from othernetwork entities.

The storage 830 may store various types of information such asinformation for an operation of the network entity and informationreceived from other network entities.

The controller 820 may control the network entity to perform any oneoperation of the above-described embodiments. The controller 820 and thetransceiver 810 do not necessarily have to be implemented into separatemodules, and may be implemented into a single component in the form of asingle chip. The controller 820 and the transceiver 810 may beelectrically connected. For example, the controller 820 may be acircuit, an application-specific circuit, or at least one processor.Further, operations of the network entity may be realized by providingthe memory device 830 storing the corresponding program code in anarbitrary component in the network entity.

The network entity may be any one of a base station (RAN. NG-RAN, eNB,gNB, NB), AMF, SMF, PCF, UDM, AUSF, AF, BSF, NEF, or UPF.

It should be noted that the constitution diagrams illustrated in FIGS. 1to 8 , diagrams of a control/data signal transmission method, operationprocedure diagrams, and constitution diagrams are not intended to limitthe scope of the disclosure. That is, all components, entities, or stepsof operation described in FIGS. 1 to 8 should not be construed asessential components for implementation of the disclosure, and thedisclosure may be implemented within a range that does not impair theessence of the disclosure even by including only some components.

The operations of the base station or the terminal described above maybe realized by providing a memory device storing the correspondingprogram code in an arbitrary component in the base station or theterminal device. That is, a controller of the base station or theterminal device may execute the above-described operations by readingand executing the program code stored in the memory device by aprocessor or a central processer (CPU).

Various components and modules of the entity, base station, or terminaldevice described in this specification may be operated using a hardwarecircuit such as a combination of a complementary metal oxidesemiconductor-based logic circuit, firmware, software, and/or hardwareand firmware and/or software inserted into a machine readable medium.For example, various electrical structures and methods may beimplemented using electrical circuits such as transistors, logic gates,and application specific integrated circuits.

In the specific embodiments of the disclosure described above,components included in the disclosure were expressed in the singular orplural according to the presented specific embodiments. However, thesingular or plural expression is appropriately selected for a situationpresented for convenience of description, and the disclosure is notlimited to the singular or plural components, and even if a component isrepresented in the plural, it may be formed with the singular, or evenif a component is represented in the singular, it may be formed with theplural.

Embodiments of the disclosure disclosed in this specification anddrawings present specific examples to easily describe the technicalcontent of the disclosure and to help the understanding of thedisclosure, and are not intended to limit the scope of the disclosure.That is, it is apparent to those of ordinary skill in the art to whichother modifications based on the technical spirit of the disclosure maybe implemented. Further, each of the above embodiments may be operatedin combination with each other, as needed. For example, an embodiment ofthe disclosure and parts of another embodiment may be combined tooperate a base station and a terminal. Further, the embodiments of thedisclosure are applicable to other communication systems, and othermodifications based on the technical spirit of the embodiments may alsobe implemented.

What is claimed is:
 1. A method performed by a network exposure function (NEF) in a wireless communication system, the method comprising: receiving, from an application function (AF), a first message requesting registration of an event subscription service to a user plane function (UPF); transmitting, to another network entity, a second message requesting information on the UPF; receiving, from the another network entity, a third message including the information on the UPF; and transmitting, to the UPF selected based on the information on the UPF, a fourth message requesting registration of the event subscription service. 